A pilot study to develop a DUI offender typology will be conducted. Prior DUI typologies are reviewed, and variables from all previously used domains, including personality, driving attitudes, impairment indices, arrest histories, age, cognitive levels, and current status variables will be included in the current study. The AUI, CSQ, CL, and 13 additional scales in prior typologies will be administered to 500 subjects in Mississippi and Colorado. A subsample will receive the LAI interview. A cluster analysis will be conducted on data from 300 of the subjects, and the analysis will be replicated using a hold out sample. Discriminant function analysis will be used as a second technique for subtype identification. A factor asymptote method will be used to identify essential and non-essential variables. Representative cases will be selected from each subtype and submitted to a panel of 10 clinical judges who will score the apropriateness of various treatment options for each case. Analyses will be conducted to determine if the appropriateness of various treatments vary systematically across identified subtypes. Additional external validation will be ascertained by use of demographic and drinking environment variables. This pilot study will be used to develop hypotheses regarding client specific treatment effectiveness.